I wrapped/integrated handlebars templates last weekend, and after understanding how the google Closure library/compiler does things, it took ~15 minutes to have it working beautifully (using basically the same technique as jayq). For a lot of the libraries, it's not a big deal.
For others, I assume that the imperative style that's so pervasive in JS makes it more difficult to use in cljs without lots of tedious macros. I'm slightly optimistic that the google Closure library, as much as I dislike the style of it, may actually end up imposing just enough structure and reasonable common practices that cljs and other languages can really interop nicely.
